Department of Chemistry, Laipat Rai (PG) College, Sahibabad-201 005, (Ghaziabad), India
The stereochemistry of the actinide elements has recently undergone considerable development and a wide variety of coordination numbers and geometries have been observed. This structural versatility arises from the lack of strong crystal field effects for the 5f-electronic configurations as well as from the large ionic radii of these metal ions, which change markedly with oxidation number, or atomic number for the actinides. To review the concept, in the present work, we wish to report the synthesis and spectral properties of some new thorium (IV) conplexes of 4-(N-(2-Hydroxybenzalidene)amino] antipyrine semicarbazone (HBAAPS) and 4-[N-Cinnamalidene)-amino] antipyrine emicarbazone (CAAPS) with the general composition ThX4.2L (X=Cl¯, Br¯, I¯, NCS¯ or CiO4¯ and Th(NO3)4.L (L=HBAAPS or CAAPS). The infrared data suggest that the semicarbazones behave as tridentate N,N,O-donors. In conclusion thorium (IV) displays coordination numbers 6, 8, 10 or 11 depending on the nature of coordinating anions of these coordination compounds.